The present invention relates to impact attenuating bodies and more particularly to such impact attenuating bodies employed in applications contemplated for engagement by vehicles or other objects moving in a generally predetermined travel direction.
Impact attenuating bodies of the type referred to above have commonly been employed in the prior art in a number of different applications. For example, they are commonly employed in connection with maintenance and surveillance vehicles used, for example, in transit areas such as highways, freeways and bridges. In such situations, even though the vehicles are highly visible and are provided with extra warning lights or other devices, they are commonly subject to collision or impact by overtaking vehicles.
Customary protective devices such as bumpers and the like do not provide sufficient protection for the maintenance vehicles in such situations. At the same time, the overtaking vehicles may also be subject to substantial damage. Impact attenuating bodies have been developed for use in such maintenance vehicles in order to provide greater protection for the vehicles and their occupants during collisions.
Generally impact attenuating bodies are elongated and are mounted, for example, on the rear of the maintenance vehicles so that an overtaking vehicle impacts the body instead of the truck. Shock absorbing material within the body not only protects the truck and its occupants during the collison but also tends to provide protection for occupants of the overtaking vehicle. In particular, it is desirable for such impact attenuating bodies to be able to gradually arrest movement of the vehicle over a selected distance of travel, for example, along one dimension of the impact body. After initial engagement of the overtaking vehicle with the body and during the selected distance of travel thereafter, the impact attenuating body is designed to dissipate the impact energy of the vehicle.
A number of such impact attenuating bodies have been provided in the prior art as indicated, for example, in U.S. Pat. No. 3,907,353 issued Sept. 23, 1975 to Dinitz and U.S. Pat. No. 4,008,915 issued Feb. 22, 1977 to Walker. These references are typical of prior art impact attenuating bodies in that they employ a plurality of similarly formed and oriented elements or cells filled with shock absorbing material in order to accomplish the purposes referred to above.
However, because of the generally substantial impact forces developed during such collisions, there has been found to remain an increasing demand for even more effective impact attenuating bodies.